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f 05 November 2001 AGE-NC Project No. 95-0106 �. Page 4.of 5 ' MW-3 and MW-6 limits the extent of-dissolved hydrocarbons northeastward of the,site. - Analytical data from..monitoring well MW-5'limits the extent of dissolved hydrocarbons north-westward.of the site.. The extent of dissolved hydrocarbons-to the east is.,,not,well ' defined.at this time; it appears that the plume of contaminated ground water may have shifted to the east. • As can'be'seen on.Table 2, TPH-g concentrations were generally higher in groundwater ' samples collected*from the offsite well MWA, than in the on:-site well, MW-1;.however', , *benzene concentrations have generally been higher in samples from MW-1'. • Continued detection of TPH-g and BTEX in ground water samples collected fromthe off-site well MW4 indicates that the plume of impacted,ground water has miated off-site towards the north, however, the general lack'of detection of hydrocarbons in the-MW-7, MW-6; ' MW-5' and MW-3 wells shows,that the plume'is not wide-spread and' has not migrated northeast of MW-4 or northwest of the former UST pit. •• The extent of the plume around MW-4 is constrained by data from MW-6 toward the north- northeast, MW-5 toward the southwest and MW-7 toward-the east relative to MW-4. The northwestern'extent of the plume from MW-4 is riot well constrained. OP The results of this and previous,monitoring events and previous soil'investigations leads AGE to conclude that. The hydrocarbons encountered in groundwater samples•from MW-1 'and MW-4 represent ' ,s a northward extension of the:hydrocarbon-impacted ground water:that had already reached its,cui-rent extent at the time the monitoring well system was installed beginning in 1996. The hydrocarbons encountered in ground water samples from MW-7 collected'.during the ' 'previou§.quarter may have been ah6malous, • The variation of hydrocarbon'concentrations in samples collected from MW=1'.and MW-4 maybe=due to.the closer'proximity of MW-1 to impacted soil left in.place near.the,former. UST'site. 6.0. RECOMMENDATIONS ' AGE recommends continued quarterly montoring of the monitoring well network. The next ; monitoring event should be`scheduled for'November 2001. Advanced GeuEnvironmental,Inc.